16663631 has 2 divisors, whose sum is σ = 16663632. Its totient is φ = 16663630.

The previous prime is 16663613. The next prime is 16663651. The reversal of 16663631 is 13636661.

Together with previous prime (16663613) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16663631 - 2¹⁸ = 16401487 is a prime.

It is a super-2 number, since 2×16663631² = 555353196208322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16663651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8331815 + 8331816.

It is an arithmetic number, because the mean of its divisors is an integer number (8331816).

Almost surely, 2^16663631 is an apocalyptic number.

16663631 is a deficient number, since it is larger than the sum of its proper divisors (1).

16663631 is an equidigital number, since it uses as much as digits as its factorization.

16663631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 32.

The square root of 16663631 is about 4082.1110959894. Note that the first 3 decimals coincide. The cubic root of 16663631 is about 255.4209681229.

The spelling of 16663631 in words is "sixteen million, six hundred sixty-three thousand, six hundred thirty-one".